Jaguar XJ (2008 year). Service manual — part 40

161

Cruise (Speed) Control

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Caution:
• RESUME should only be used if the

driver is aware of the set speed and
intends to return to it.

• It is not recommended to resume

set speed when a low gear is
selected as excessive engine
speeds will occur.

Cruise control will switch off and clear
the memory when:
• The ignition is switched to position 0.
• A fault occurs. The cruise control

system will switch OFF and cannot be
used until the fault is cleared.

Cruise control automatic switch off

Cruise control will switch off but the set
speed will remain in the memory when:
• The CANCEL button is pressed.
• The brake pedal is pressed.
• Speed falls below 26 km/h (16 mph).
• Neutral, Park or Reverse gear

positions are selected.

• Dynamic Stability Control (DSC) is

operating.

• The difference between the actual and

set speed is too great.

• The vehicle reaches a maximum

speed of 230 km/h (144 mph).

• The accelerator pedal is used to

accelerate beyond the set speed for
too long a period.

Adaptive Cruise Control (ACC)

162

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Adaptive Cruise Control (ACC)

PRINCIPLE OF OPERATION

The Adaptive Cruise Control system is
designed to aid the driver to maintain a
gap from the vehicle ahead or a set road
speed if there is no slower vehicle ahead.
The system is intended to provide
enhanced operation of the vehicle when
following other vehicles which are in the
same lane and travelling in the same
direction.

!

WARNING:

Adaptive Cruise Control is not a
collision warning or avoidance system.
Additionally, Adaptive Cruise Control
will not react to:
• Stationary or slow moving vehicles

below 10 km/h (6 mph).

• Pedestrians or objects in the

roadway.

• Oncoming vehicles in the same

lane.

The Adaptive Cruise Control system is
based on the use of a radar sensor which
projects a beam directly forward of the
vehicle so as to detect objects ahead.

The radar sensor is mounted behind a
cover on the left-hand side of the lower
cooling aperture, to provide a clear view
forward for the radar beam.
• Only use Adaptive Cruise Control

when conditions are favourable, that
is, straight, dry, open roads with light
traffic.

• Do not use in poor visibility,

specifically fog, heavy rain, spray or
snow.

• Do not use on icy or slippery roads.
• It is the driver’s responsibility to stay

alert, drive safely and be in control of
the vehicle at all times.

• Keep the front of the vehicle free from

dirt, metal badges or objects,
including vehicle front protectors,
which may prevent the sensor from
operating.

• Do not use ACC when entering or

leaving a highway.

163

Adaptive Cruise Control (ACC)

R

USING ACC

The system is operated by switches
mounted on the steering wheel. The driver
can also intervene at any time by use of
the brake or accelerator pedal.

The steering wheel switches operate as
follows:

1. RESUME - to resume the set speed

retained in memory.

2. SET - to set the speed or

increase/decrease the set speed
when the speed has been set.

3. CANCEL - cancels cruise control, but

retains the set speed in memory.

4. GAP - increase or decrease.

Setting the speed

Accelerate as normal until the required
speed is reached.

Press the SET (+) button briefly and the
vehicle speed will then be stored in the
memory and the system engaged. The set
speed will be displayed on the message
centre.

Changing the set speed

There are three ways to change the set
speed:
• Accelerate or brake to the required

speed and press the SET (+) button.

• Increase or decrease the speed by

pressing and holding either the
SET (+) or (–) button until the required
set speed is shown on the message
centre. The vehicle speed will
gradually change to the selected
speed.

• Increase or decrease the speed in

steps of 2 km/h (1 mph) by briefly
pressing the SET (+) or (–) button.

ACC operates between approximately
34 km/h and 180 km/h (20 mph and
110 mph) dependent on the country
specification.

Set speeds outside this range will not be
captured.

The ACC may apply the brakes to slow
down the vehicle to the new set speed.
The new set speed will be displayed on
the message centre until ACC is
cancelled.

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E86372

SET SPEED

80 KM(50 MPH)

(80 KM/H)

Adaptive Cruise Control (ACC)

164

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Entering the follow mode set gap

!

WARNING:

When in follow mode, the vehicle will
not decelerate automatically to a stop,
nor will the vehicle always decelerate
quickly enough to avoid a collision
without driver intervention.

Once a set speed has been selected, the
driver can release the accelerator and the
set road speed will be maintained.

When a vehicle ahead enters the same
lane or a slower vehicle is ahead in the
same lane, vehicle speed will be adjusted
automatically until the gap to the vehicle
ahead corresponds to the preset gap. The
vehicle is now in follow mode.

The warning indicator in the
instrument panel will be
illuminated,

The message centre will display the gap
set.

The vehicle will then maintain the
constant time gap to the vehicle ahead
until:
• The vehicle ahead accelerates to a

speed above the set speed.

• The vehicle ahead moves out of lane

or out of view.

• A new gap distance is set.

If necessary, the vehicle brakes will be
automatically applied to slow the vehicle
to maintain the gap to the vehicle in front.
The maximum braking which is applied by
the ACC system is limited and can be
overridden by the driver applying the
brakes, if required.

Note: Driver braking will cancel Adaptive
Cruise Control.

If the ACC system predicts that its
maximum braking level will not be
sufficient, then an audible warning will
sound while the ACC continues to brake.

This is accompanied by a red warning
indicator and DRIVER INTERVENE will
be displayed on the message centre.
The driver should take IMMEDIATE
action.

When in follow mode the vehicle will
automatically return to the set speed
when the road ahead is clear, for instance
when:
• The vehicle in front accelerates or

changes lane.

• The driver changes lane to either side

or enters an exit lane.

The driver should intervene if appropriate.

Changing the follow mode set gap

The gap from the vehicle ahead can be
decreased or increased by pressing the
gap setting rocker switch on the steering
wheel.

Four gaps are available and the selected
gap setting will be displayed on the
message centre when the rocker switch is
pressed.

After the ignition is switched ON the
default gap will be automatically selected
ready for ACC operation.

GAP